Substrates of the semiconductor industry are handled, inspected and/or measured in inspection machines or coordinate measuring machines. Substrates for the semiconductor industry are, for example, wafers, masks for the production of wafers or flat panel displays. The inspected and/or measured substrates may, for example, be disk-like wafers usually consisting of silicon or gallium arsenide. However, substrates may also be masks having structures applied thereto, which serve as patterns for wafer exposure. During production and the inspection of the semiconductor wafers, the substrates are transported in various types of cartridges to various work stations, where they must be inserted into the respective work station. The transport may be manual or automated.
The work stations serve various purposes in the treatment of the substrates, such as inspection, measurement or processing of the substrates. During inspection, the substrates are optically inspected particularly for undesired particles on the substrates or for defects in the structures on or in the surface of the substrates. The inspection may be performed by the user or automatically with the help of an electronic camera. In such work stations or also in separate ones, measurements may additionally be performed on the substrates. Width (CD), distance or thickness of the structures are preferably measured in the coordinate measuring machine. In most cases, the systems or devices for these applications of inspection and/or measurement include a central work station capable of having at least one further module added thereto. The further module allows performing further examinations and/or manipulations of the substrate.
Further common requirements for such systems are high reliability, simple operability and uncomplicated maintenance. At the same time, there are high requirements with respect to substrate handling, such as safety, speed and clean handling. The transfer of the substrates from the system to the module is set once so that the handling robot knows a defined transfer position. If the module is removed for maintenance purposes, it is important to ensure that the once set position is re-occupied when the module is again mounted to the system.
Handling the substrates means transferring the substrates from the substrate supply module to one of the work stations. It is important that the substrates reach the work station and are finally returned to the substrate supply module unerringly and without being damaged.
DE 42 35 677 A1 discloses a transport unit for workpieces in a chamber of a vacuum processing installation, wherein the workpieces are transported in the area of an opening. Since the workpieces are handled in the same plane of the opening, several chambers may be combined in a modular way to form an installation configuration.
EP 0 899 776 A1 discloses an apparatus for the intermediate storage of wafers in a wafer processing installation with the help of an exchanger. A removal area may be arranged in any place on a front or lateral side wall of the exchanger.
None of these two publications discusses the type of connection or the connectors used between the units to be connected.
DE 100 53 232 C2 describes a system including one or more substrate supply modules and at least one work station comprising connecting elements on two or more different side walls, the connecting elements cooperating with corresponding connecting elements in at least one side wall of each substrate supply module. Examples of such connecting elements are, in particular, so-called kinematic couplings.
For many processing and inspecting steps, it is very important that the various areas between which there may be a transfer of substrates are arranged in exactly defined spatial alignment with each other. Therefore, exact alignment of the modules with respect to each other is generally essential. For all known ways of connecting several modules of a work station, the transfer position of the substrates to the station continues to be decisive. The exact transfer position can only be ensured by aligning the stations precisely to each other or to the work station respectively.